Boost Cut Engaged Below Parameters

s300 and SManager software questions & answers
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Spunkster
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Re: Boost Cut Engaged Below Parameters

Post by Spunkster »

Post a picture of the inside of the ECU
jgauth4468
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Joined: Wed Oct 21, 2020 4:14 am

Re: Boost Cut Engaged Below Parameters

Post by jgauth4468 »

Can do! Anything specific you want to see?

I did a little electrical inspection on the Pressure Switch side, per Honda (and AllData) service. I get KO battery voltage at the switch connector. On the sensor, I get 0.1-0.2-ohm across the 2 pins (passes continuity requirement). Regarding the ground side of the circuit (black wire to G100). I verified continuity via test light. Connected like to battery source, test light probe contacting ground within connector, the light illuminates. To further verify the integrity of the ground, I verified that a light which requires 2.0amps would light up strong, and it does. With that, electrically, the VTEC Pressure switch circuit is OK.

I am going to verify oil pressure at the pressure sensor tomorrow.

Let me know what pics you need.

Thanks!!

-J
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Spunkster
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Re: Boost Cut Engaged Below Parameters

Post by Spunkster »

Pictures of the inside of the ECU from top and bottom
jgauth4468
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Joined: Wed Oct 21, 2020 4:14 am

Re: Boost Cut Engaged Below Parameters

Post by jgauth4468 »

Attached are 4 pictures.
1: as pulled from the vehicle
2: Cover removed, Analog & USB cord removed
3: Hondata removed
4: Bottom of board

I gave both side of the board a good visual, and good smell. Not seeing anything odd, nor any burn electrical smells. This ECU is my "good" one, which I trust. Again, got this ECU from a good source, and is maybe 6 months old.

I have another ECU, which I had originally acquired from an ebay seller ~2 years ago, and had the same issue. My original factory ECU is still here, but isn't chipped for hondata, and therefore won't run the 440cc injectors, nor the 4-bar MAP. The original factory ECU had no issue with VTEC activation, on the original setup (same turbo, pistons & rods, smaller injectors, factory intake, 5-6psi with boost check valve on the MAP).

Thoughts?

-J
Attachments
ECU_4.jpg
ECU_4.jpg (1.41 MiB) Viewed 899 times
ECU_3.jpg
ECU_3.jpg (1.45 MiB) Viewed 899 times
ECU_2.jpg
ECU_2.jpg (1.51 MiB) Viewed 899 times
ECU_1.jpg
ECU_1.jpg (1.38 MiB) Viewed 899 times
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Spunkster
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Location: Hondata

Re: Boost Cut Engaged Below Parameters

Post by Spunkster »

Post the calibration and a datalog showing the current problem now that other issues have been resolved.
jgauth4468
Posts: 19
Joined: Wed Oct 21, 2020 4:14 am

Re: Boost Cut Engaged Below Parameters

Post by jgauth4468 »

Spunkster

I pulled the attached calibration from the ECU. I let the engine come up to temp, then collected the attached datalogs (2nd Gear and 3rd Gear).

At VTEC x-over (RPM & throttle parameters) it registers the boost cut.

I did collect additional datalogs with a few different Parameters altered (VTEC oil pressure switch OR Disable spool OR Launch Control "off"). These each individually had the same result. I verified that turning VTEC off, wide open throttle, there is no issue to go to 6800RPM.

I need to take a careful look to understand the data.

I appreciate the time & assistance

-J
Attachments
2022-03-10 Pulled from ECU 3G.s3d
(53.58 KiB) Downloaded 70 times
2022-03-10 Pulled from ECU 2G.s3d
(84.05 KiB) Downloaded 59 times
2022-03-10 s300 Pulled from ECU.skl
(43.4 KiB) Downloaded 68 times
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Spunkster
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Re: Boost Cut Engaged Below Parameters

Post by Spunkster »

The problem is that your ECU is grounding through the VTEC solenoid and it acts as a rev limit when VTEC engages. YOu need to try your ECU in another vehicle and you will see that it operates as it should. If it does, then you will need to correct the wiring issue in your vehicle.
jgauth4468
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Joined: Wed Oct 21, 2020 4:14 am

Re: Boost Cut Engaged Below Parameters

Post by jgauth4468 »

Got snow last night. Plus busy weekend with kids activities. So, going to come up with next weeks game plan...

Is there another method of testing that does not involve testing the ECU in a different vehicle?

I don't have another car to test it in, nor any friends with Hondas. I've reached out to those on the JDM Detroit FB page to see if there's anyone that can assist. Anyone on the forum in SE Michigan able to assist?

Spunkster, I'm trying to understand what you're indicating is potentially occurring. Are you saying that either the VTEC solenoid wire and/or Pressure Switch wire, from the ECU to the VTEC assembly, is shorting across a different circuit?

Just thinking... I have some ECU harness pins. I could easily make a test wire, and substitute that in the ECU connector (PIN A4 or D6) and go directly to the solenoid and pressure sensor, and not use the factory harness for the 2 suspect circuits. If the VTEC functions using the "substitute" wire, I could remove one of the test wires, to determine which circuit is the issue.

Thoughts?
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Spunkster
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Re: Boost Cut Engaged Below Parameters

Post by Spunkster »

You need to first determine if the ECU is working as it should in a working vehicle. If it does, then you need to start looking a the wiring and grounds in your vehicle. You should not start making wiring changes before testing.
jgauth4468
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Re: Boost Cut Engaged Below Parameters

Post by jgauth4468 »

Status Update 11-Jul-2022

Issues resolved. vTEC is working without issue. The latest progress on the project, and casual cruising with my son, has yielded results.

The question others would ask... "what did you do to fix the issue".

There was 1 code present for IAC (code was no surprise, as I deleted IAC when I installed the Skunk2 throttle body and intake). Buried in the Idle Parameters (not really buried, but it's there) there is the option for IAC Error... I checked the "Disable IAC Error". Also, I applied rubberize truck bed liner to my trunk floor, forcing a relocation of the battery ground. I cleaned the lug on the ground cable (which was not in bad shape).

Which fixed the issue... not sure, but vTEC works like a champ now. If I had time to dedicate to the issue, and didn't always start at Step 1 of diagnosing it, I likely would have resolved it faster.

Step 1 : Like is always suggest, check your grounds... ALL OF THEM
Step 2 : Address the obvious (the MIL code for IAC)
Step 3 : If it's none of those, put on the "Eric O" hat and systematically work the problem checking circuit robustness (is the circuit in one piece and can it carry load / current)... I started & confirmed this on the vtec circuits but moved onto the trunk coat project.

I hope this case helps someone with their issue

-J
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